I have the same problem with my NWZ-A818. There is no difference when the volume is at 20/30 compared with 30/30. I have checked the service manual for the NWZ-A818 and the access method is the same as for the NWZ-A808 that has been posted here. However, like the other users i cannot seem to access the service menu. 1. Turn Power On. 2. Hold "Back" until the home menu appears. 3. Set "Hold" on 4. While holding down the "Option" button, press Up-Right-Down-Left-Up-Play-Up-Left-Down-Right-Up-Play 5. Set "Hold" off However, after this step nothing happens. Can anyone who got this to work see anything I am doing wrong? If anyone wants, I can attach the service manual for the NWZ-A818. Thanks a mil for any help!